Piston construction



Nov, 1, 193 2. N. J. BUREN PISTON CQNSTRUGTION I Filed Feb, 13, 1930 2 Sheets-Sheet =1 gwwmtgz @mwmu Nov. 1, 1932. v N. J. BUREN PISTON CONSTRUCTION Filed Feb. 1:5, 1930 2 Sheets-Sheet 2 gwue ntoz Sgewkom fifbxrverm.

Patented Nov. 1, 1932 "WW non 3. RUBEN, OF'TACO, WASHINGTON rrsron cons'rnnc'r ron 7 Application filed February 13, 1980. Serial No. 428182.

This invention relates to improvements in piston construction of the type generally employed in the working cylinders of internal combustion engines.

a Heretofore, it has been common practice to'provide pistons having one side of the piston skirt slotted in order to provide means for taking up excessive skirt expansion. Such practice is objectionable because no 30 special means has ever been provided to neutralize the flexibility caused by the slotting of the skirt. The disadvantages of a flexible piston skirt is known throughout the automotive industry. Flexibility of the skirt causes the piston to chatter or vibrate from connecting rod forces because it is not stifi' enough to resist them. This results in noisy action, loss ofpower throu h wearing the faces of the iston rings slightly rounded, 2 resulting furt er in oil bumping.

), ible piston hinges opposite the slot where there is no means provided to stiffen that portion of the skirt.

Definite means for overcomin the disadvantages above set forth is found by providing eccentric ribbing of eccentric contour in the cross section to oifset the flexibility of the usual split skirt piston. The eccentric ribbing replaces a large amount of the rigidity lost when split-tin the piston skirt. The thickest portion o the eccentric ribbin is placed opposite the slots and is embodie at present in two ways:

'FirstAn eccentric skirt with one eccentric upper rib and a concentric bottom rib for machining;

SecondA concentric skirt with two or three eccentric ribs, depending upon the.

will overcome the above disadvantages and which will comprise no more than the usual number of parts commonly used in present day piston construction.

Other objects and advantages of the invention, will become apparent during the course of the following description, forming a part of this specification and in which,

- Figure 1 is a vertical sectional view of the preferred form of piston construction emg9 ploying the single eccentric reinforcing rib ormed integral with the inner wall 0 the piston;

Figure 2 is a transverse sectional view taken on line 22 of Figure 1 showing the fig eccentric formation of the piston skirt wall arliod also the enlarged cross-section area of the r1 Figure 3 is. a cross-sectional view taken transversely throu h the lower portion of the m piston illustrated 1n Figure 1 and shows the v enlarged portion of the eccentric piston skirt being opposite of the slot therein; y

Figure 4 is a vertical cross-sectional view of a modified form of this invention and shows the skirt portion of the piston formed concentric with three eccentric ribs formed integral with the piston skirt in order to more thoroughly reinforce the same;

Figure 5 is a vertical cross-sectional view o of a further modified form of this invention and this view is taken on the longitudinal axis of the wrist pin bearings and illustrates th: concentric skirt portion and two eccentric r1 s Figure 6 is a vertical cross-sectional view of Figure 5 taken at right angles to the axis of the wrist pin hearings to illustrate the arrangement of the eccentric reinforcing ribs Figure 7 is a transverse sectional view 99 taken on Figure 5 on'the line 7-7 showing the manner in which-the upper eccentric rib is gfiormed relative to the wrist pin bearing; an

Figure 8 is a transverse sectional view of Figure 5 taken on line 8-8 showing the crosssectional area of the. lower reinforcing rib relative to the vertical slot.

For a more detailed description of the drawings, attention is directed thereto wherewe in the numeral 5 will be generally referred to to designate a piston havin the usual piston ring grooves 6 and wrist pin arings 7. The wrist pin bearings 7 are braced to the piston 5 by enlarged. ribs 8 which terminate at their upper en s at the top wall.

A skirt portion 9 is formed on the lower portion of the piston 5 and it will be noted that the skirt 9 is split as at 10 vertically which terminates in a horizontal slot 11 formed in the upper end of the piston 5. This slot is provided for compensating piston clearances and allowing expansion and contraction of the skirt. It is to be noted that the skirt portion 9 isformed eccentrically in Figure 1 and that the thickest portion of the eccentric skirt 11 is directly opposite the vertical slot 10 whereby the same will be braced and formed more rigid. The skirt portion 9 is formed concentrically in Figures 4 and 5. The difierence in design is to compensate for the large wrist pin lock bolts used in some engines of small bore. The latter case using a piston as in Figure 1.

Formed integral with the inner wall of the skirt 9 is an eccentric rib 12 which is formed of the same material as the piston skirt and which is also formed correspondingly to the thickness of the piston skirt 9. As illustrated in Figure 2, the largest portion of the eccentrio integral rib 12 is also opposite the slot 10 whereby the free ends of the skirt adjacent the slot 10 will be formed more rigid and prevent collapsing of the piston skirt.

A circular cut away portion 13 may be formed between the piston ring collecting oil in the cylinder wa and draining it back to the crank case through the apertures 14 which are arranged in spaced relation as illustrated in Figure 1. The groove 13 is used in conjunction with the usual oil control piston ring placed in the bottom top ring-groove. The groove 13 drains the excess oil which cannot be passed through slot 11.

Attention is directed to Figure 4 wherein is shown the piston 5 having the usual piston ring grooves 6 and the wrist pin bearlngs 7.

As shown in Figure 4, three or more eccentric ribs 12 may be provided for further reinforc ing the skirt portion of the iston 5. The skirt portion 9' is not forme eccentric but depends largely upon the eccentric ribs 12 for furnishing the necessary rigidity thereof.

In Figures 5 to 8 inclusive, is illustrated a piston 5" of a modified construction having the usual wrist pin ring surfaces 7 The wrist pin bearings 7 are braced in the head of the and the eccentric ribs 12" are formed inte-.

ooves 6 for iston ring grooves 6" and the gral with the inner walls of the piston skirt 9 and as illustrated in these figures, only two eccentric ribs 12" are employed for furnishing the required rigidly to the piston skirt. An annular cut away portion 13" is formed between the piston ring grooves for collecting oil which is drained back to the bearings of the wrist pins through ports 14" which terminate in the inner walls of the piston head 5".

The value of groove 13 is in allowing the compression ring in the groove immediately above it, to act as both compression ring an scraper rin Heretofore, all oil control in pistons has en confined to the lowest groove as illustrated at 6, and modern engines have such a great volume of oil that additional preventive means must be provided to reduce the oil consumption. Natural compression losses blowing by the rings above groove 13,

the eccentric ribs re ative to the piston skirt.

It is to be form of wrist pin bearing arrangement may be provided without departing from the further understood that any spirit of the invention or the scope of the sub-joined claims.

Having thus described my invention, what I claim is 1. A piston construction of the character described, comprising a piston head, annular piston packing ring grooves formed in the ead, a piston skirt depending from the piston head havin a vertical slot extendmg' rom the bottom 0 the skirt to approximate.- ly the top thereof and terminating in a horizontal slot, and eccentric gral withthe inner wall of t e piston skirt and concentrically disposed relative thereto wherein the largest areas of the eccentric rmgs are directl opposite the vertical slot of the skirt where y the piston skirt will be made more rigid.

2. In a piston construction, com rising a piston head having a series of an ar packingrmg grooves, an oil return groove formed between two of the above mentioned piston packing ring grooves for communicating with the oil return groove with the interior of the piston head, a split skirt depending from the piston head, and means for reinforcin the piston skirtat a oint opposite the sp 't portionthereof, sai means comformed intemamm prising me or more eccenwic wiles fomad mtegral with the er wall 0:? the pislon skirt and the reduced and; of the laric rib bein in close relation to the split portion of the s in, and the enlarged POElSiOfi nffizhs @ccentric rib at a, point opposita the split portion of the sfirt.

In testimony whereof I y si 1' a bum.

NEWTON J. $2 I EH. 

